Lubricating oil composition

Abstract

A lubricating oil composition of the invention contains: a base oil; at least one of acid phosphate represented by formulae (1) and (2) below; and an antioxidant. In the above formulae: R 1 , R 2 and R 3 are alkyl groups; and at least one of R 1 and R 2 has 20 to 30 carbon atoms while R 3 has 20 to 30 carbon atoms.

1 . A lubricating oil composition, comprising:
 a base oil;   at least one of acid phosphate represented by formulae (1) and (2) below; and   an antioxidant,   
       
         
           
           
               
               
           
         
         wherein: 
         R 1 , R 2  and R 3  are alkyl groups; and 
         at least one of R 1  and R 2  has 20 to 30 carbon atoms while R 3  has 20 to 30 carbon atoms. 
       
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein at least one of R 1  and R 2  has a side chain. 
     
     
         3 . The lubricating oil composition according to  claim 1 , wherein R 3  has a side chain. 
     
     
         4 . The lubricating oil composition according to  claim 2 , wherein the side chain has 6 to 18 carbon atoms. 
     
     
         5 . The lubricating oil composition according to  claim 1 , wherein the antioxidant is at least one of a phenolic antioxidant, an amine antioxidant and a sulfur antioxidant. 
     
     
         6 . The lubricating oil composition according to  claim 1 , wherein the acid phosphate is contained in a range from 0.01 mass % to 3 mass % of a total amount of the composition. 
     
     
         7 . The lubricating oil composition according to  claim 1 , wherein the lubricating oil composition is suitable for use in a shock absorber. 
     
     
         8 . The lubricating oil composition according to  claim 7 , wherein the shock absorber is suitable for use in a four-wheel automobile.